Review of the Kefine Klean

Introduction

Kefine is another company that I genuinely admire and am a fan of. In my opinion, they sit well among my favorites, like Kiwi Earrs and Simgot. Even though they only have three IEMs in their lineup, including their latest release, I find it remarkable that they have gained so much following and respect in the audiophile community. Personally, I have loved both of their IEMs, Klanar and Delci, for their unique approaches and market positions. As mentioned earlier, they have released another budget-friendly IEM called Klean. I was fortunate enough to get my hands on it for review purposes, but before we proceed, I would like to clarify a few points.

Disclaimer

*Since this unit tour was organised by the kindly people at Linsoul, I am grateful to them. As I've said in all of my evaluations, the same is true for this one: all of the concepts I've expressed below are entirely my own, original ideas that haven't been influenced by anyone else. If interested, go to this link.
*I am not associated with the connection, and I receive no financial assistance from anyone.
*For the remainder of the review, I will refer to these IEMs as “Klean.”
*I am using different ear-tips for convenience and better versatility.
*Finally, I will only evaluate the Klean based on its performance, even though I will explain how it feels and seems physically and aesthetically.
*My evaluation is based on the standard nozzles that were pre-applied to the IEM. I will discuss the other type of nozzles in a separate section of this review.

Specification

Klean is a single dynamic driver that houses two 10mm DLC diaphragm drivers. The shells are small and lightweight, which contributes to their excellent seal, comfort, and fit. During my testing, I found Klean to be very comfortable for extended listening sessions. The shells are made of metal alloy with a durable build reinforced by a screw design. The faceplate has a minimalist design that exudes a cool and premium feel. The cable that comes with the IEM is a generic cable that is suitable for an IEM priced under $50. It feels nice in the hand and is well-behaved. The cable has two-pin connectors and ends in a 3.5mm termination plug. There’s also a variation of this cable that includes a microphone. The other accessories included are three pairs of eartips in different sizes, a generic carrying case that came with the last two of Kefine’s releases, and another pair of tuning nozzles that provide different tuning options. In terms of technical specifications, Klean has an impedance of 32Ohms and a sensitivity of 107dB. The frequency response range is from 20Hz to 20kHz.

Sound

The last two IEMs I’ve heard from Kefine are the Delci and Klanar. Both are excellent and positioned well in the audiophile market as one of the best, which seems true from my perspective. However, when it comes to the Klean, I was surprised. First, they were able to produce such a high-quality IEM in both the physical and sonic aspects. Second, the way they tuned these IEMs definitely puts them in the all-rounder category. The tuning is truly impressive—no unique technology, no DSP, just a driver and a dedicated or custom-made body for the driver. For me, the tuning leans towards a balanced sound signature with a lot of sustained vocals and instruments across the frequency response. The bass is provocative and well-defined, but not overpowering or invasive. The midrange is well-flourished and tonally rich, maintaining the timbre and technical chops of the instruments and vocals. The treble is well-done by many IEM manufacturers, but in the Klean’s case, it’s even smoother and more refined. Let’s delve deeper into the sound to find more about it.

Treble

Starting with the treble, I believe it has a decent forwardness that brings a soothing experience when properly elaborated. The treble has a richness and a refined sense of vocals and instruments in a vast, spaciousness. This response is not well-known to satisfy your desire for sharp and crisp notes, but rather a natural, timbre-like sound that is almost relaxing to hear. The peak around 13-15kHz brings that sense of air and pushes the shimmer and sparkle in the mix to engage the listener. Personally, I believe that the Delci lacked this quality and brought more of that midrange forwardness compared to Klean. I think that the way Klean presents the upper extension is more attention-seeking and satisfying. Now, the upper treble, as mentioned, has a great extension with the vocals and instruments sounding fuller and richer with a decent amount of details and clarity while pushing out hits of shimmer and bite in the presentation. When it comes to the lower treble, I think it is what gives the upper extension the weight to bring this fullness and richness while also maintaining the bite in the presentation. The forwardness in the lower treble brings the vocals and instruments just right enough to sound lively and engaging. The quality of the notes brings a mesmerizing experience, as the notes don’t shower a lot of energy nor the forwardness in the mix that results in a somewhat mature-like sound. Listening to tracks like Everywhere by Fleetwood Mac, the percussion in the beginning of the song has that soothing, glittering quality that is just right. It doesn’t mask anything but surfaces well enough to sound captivating. The vocals also sound complete and full, extending really well and far, which reminds me of my Prestige LTD. Overall, the presentation of the treble region is extensive, smooth, and natural-like.

Mid Range

The budget segment of the audiophile market has come a long way, and it seems like they are now closer to mimicking the true characteristics of high-end equipment. In my opinion, the Klean is an excellent example of this. If I compare it to Delci, an IEM from the same company, I believe the Klean offers a truly magical listening experience. The midrange sounds rich and safe, with a balanced and precise note placement. The dynamic quality of the Klean is brought out by the response of the midrange sounds, which are well-resolved with a great sense of space between the vocals and instruments. The Klean provides a fulfilling listening experience, without the typical forward-sounding IEMs that can lead to clarity and sharpness, which can sometimes result in shrills, peaks, or shouts. The Klean offers a well-flourished preset that shows promise in terms of tonality while also subduing any sense of peaky, hot, or shrill characteristics. The upper midrange provides decent forwardness to bring out the vocals and instruments’ dynamics and presence, allowing the space to be filled without congestion due to its open and spacious sound. The vocals and instruments sound fuller and more complete, enabling them to scale to their fullest potential. However, there are certain tracks that made me feel a lack of forwardness. Fortunately, the tunable nozzles allow me to be satisfied with the sound. I will discuss these nozzles in more detail later. The lower midrange is well-presented in the mix, bringing a warm and natural quality to the notes. The notes retain good weight, influencing the higher frequencies and creating a harmonious sound. Listening to tracks like “Somebody That I Used to Know” by Gotye is truly incredible. I am fascinated by how diverse and well-spread out the vocals and instruments are. Both the instruments and vocals sound distinct and well-balanced without blending into each other. Especially when it comes to the drums, which sound incredibly clean and unique while still maintaining the overall structure of the tracks and the individuality of each instrument and vocal. I believe that sounding so different and unique doesn’t necessarily require advanced technical features like other IEMs in the market. As a result, the presentation of the midrange region is rich, fuller, and dynamic.

Bass

Alright, the bass is done the audiophile way. It delivers a satisfying and engaging experience while producing a good amount of quality and quantity. The bass has a great texture and details, and it creates a nice weight and depth in the mix. I believe Klean brings a response where the bass feels like an integral part of the entire presentation rather than acting independently. This blendfulness and the quality of the notes make it a great-sounding bass. The emphasis is similar to the Delci, which is the sub bass, but I think the response is softer in the sub bass, which helps bring the mid bass out in a cleaner way compared to the Delci. The deep extension provides a pleasant, subtle rumble and impact that meets the heft and necessity of the lows to sound low. When it comes to the mid bass, the drums and bass guitars have a good, thumpy, and meaty presence, but they’re not very prominent in the mix or filling the entire response. The response is well-saturated due to the positioning of the notes and their interactions, as well as the presentation, which is well-regulated. The bass has sufficient control to influence the warmth into the lower mid range while preventing it from becoming muddy, bloated, or booming. Listening to track Rumble by Skrillex sounds fantastic but not particularly enjoyable. The notes have great texture whenever the drop hits and sound complete and full, but the impact is not forward or prominent in the mix. However, when it comes to listening to tracks like Kokoronashi by Majiko, the lows sound clean and refined. The vocals remain unaffected and distinct, and the same can be said about the other instruments. Therefore, the overall presentation of the bass region is well-controlled, detailed, and pleasant.

Technical Performance

Coming to technical agility, I believe Kefine performed exceptionally well, particularly in terms of stage presence, separation, and imaging. In comparison to its peers, it excelled in these areas. However, I do acknowledge that it could have been even better, which would have increased the cost of its production. Therefore, I must say that I am quite satisfied with its overall performance. Let’s delve deeper into specific aspects.

Soundstage, Sound Imaging & Separation

The soundstage is incredibly holographic, with a deep and wide soundstage that creates a vast, spacious, and airy area surrounding the listener. This expansive soundstage, coupled with its excellent imaging characteristics, gives the impression of a large soundstage that is both clear and precise. While it may not be the sharpest or most clear sound, it offers a clean and accurate response. One of the standout features of this IEM is its exceptional separation. The distinction between notes is remarkable, allowing me to easily pinpoint the source of each sound with great clarity. This remarkable separation enhances the overall presentation, giving the stage and imaging a sense of impeccable technicality.

Speed & Resolution

Coming to the resolution, I believe the macro and micro details are adequately presented in the mix. However, I do feel that while the macro details are well-exposed, the micro details are slightly lacking. The attack and decay of the notes are nicely paced to create a natural-sounding timbre, but I believe the resolvability is good.

Sound Impressions 

Tuning Nozzles

As mentioned in the disclaimer, I reviewed these IEMs with the standard installed nozzles, which are silver. However, they also come with another pair of nozzles that have a black filter. These nozzles not only alter the sound but also present a completely different experience compared to the silver nozzles. In my opinion, the Klean is the true two-in-one IEM. It can almost satisfy anyone’s needs in terms of bass, midrange, or treble. The Klean with the black nozzles presents a more mid-centric sound. The bass and treble are slightly tamed, while the midrange is elevated, resulting in a forwarded midrange presentation. Vocals and instruments sound clearer and sharper, with a leaner presentation rather than the rich sound produced by the silver nozzles. It’s like going from a balanced-sounding IEM to a more neutral-like tuned IEM. As the upper midrange is elevated and the lower midrange is subdued, the lack of weight and warmth is suddenly felt. However, the more extended vocals and instruments bring a more transparent and clear sound that captures the listener’s attention. The bass on the other hand sounds more controlled and punchier than thumpy and retracts much faster after the impact of the low notes. Surprisingly, like with the silver nozzles, any offensive characteristics are kept at bay and don’t enter the mix. Overall, as the presentation shifted to a more midrange-focused sound, it became more neutral.

Sources

Sony WM1A - While listening to Klean with WM1A, I immediately noticed a distinct difference in the midrange. The response sounded more forward, bringing the vocals and instruments to the forefront and making them the stars of the show. The treble also sounded clearer and crispier compared to the pairing of Klean with the M15S. Additionally, the bass had a more wholesome and present sound, which added an engaging and enjoyable element to the listening experience.

FiiO M15S - While listening to Klean with M15S, the overall response sounds more forwarded and energized in all aspects. However, the bass sounds more controlled, while the treble is more forwarded. Although this enhances the clarity and detail of the sound, it somewhat narrows the stage’s reach for the listener. Nevertheless, I do notice that the midrange sounds more defined and distinctive.

Tracks

Millet - Anytime Anywhere
Anri - I can’t stop the loneliness
Kohana Lam - A Few Sentimental
Kohana Lam - Loving Me, Loving You
Uru - Kimino Shiawasewo
Uru - Kamihitoe
Kujira Yumemi - Kenka
Majiko - Kokoronashi
Anly - Sukinishinayo
Kohama Lam - A Few Sentimental
Kohana Lam - Loving Me, Loving You
Miliyah - Kono Yumega Samerumade
Rokudenashi - The Flame Of Love
Yu-Peng Chen - A New Day with Hope
Yu-Peng Chen - Another Hopeful Tomorrow
Yu-Peng Chen - For Riddles, for Wonders
Valentino Khan - Satellite
Kai Wachi - Happier By Now
Jawns - Erotica
ISOxo - how2fly
Kai Wachi - Happier By Now
The
The Weeknd - Popular
YUNGBLUD - When We Die(Can We Still Get High)
Bring Me the Horizon - Kool-Aid
Middle Kids - Bend
FLETCHER - Leads Me On
Loathe - Aggressive Evolution
The Weeknd - Save Your Tears
Sigrid - Burning Bridges
AURORA - Black Water Lilies
AURORA - Runaway
X Ambassadors - Renegades
Lupe Fiasco - Words I Never Said
Macklemore & Ryan Lewis - Can’t Hold Us
Gotye - Somebody That I Used to Know
Jay-Z - Run This Town
Lady Gaga - Poker Face
Lady Gaga - Just Dance
Ladytron - Ghost
Travis - Love Will Come Through
LINKIN PARK - Somewhere I Belong
DJ Shadow - Six Days (Remix)
Hoobastank - The Reason
Ricky Martin - I Don’t Care
Tool - 7empest
Tool - Vicarious
A Flock of Seagulls - Space Age Love Song
Zack Hemsey - Vengeance
Elton John - I’m Still Standing
The Moody Blues - Nights in White Satin
Michael Sembello - Maniac
Guns N’ Roses - Sweet Child O’ Mine
A.R. Rahman - Kun Faya Kun

Conclusion

In conclusion, I believe Kefine truly set the standards and established the baseline for how an IEM should sound in the budget segment of the IEM market. Kefine demonstrated remarkable skill in maintaining a low price point while delivering a product far exceeding its weight. Personally, I consider this to be the best budgeted IEM available in the market, particularly for its ability to offer two distinct tuning options within the same form factor. Therefore, I wholeheartedly recommend this product to anyone and everyone, especially those who are new or just beginning this passionate hobby.

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